This application describes structured organic light-emitting diodes (OLEDs) and procedures for the fabrication of structured OLEDs.
The importance of OLEDs and especially the importance of the OLED technology for displays, lighting applications and signage is steadily increasing. Due to their simple and economic processing, OLED components are predestined to represent non-moving, i.e., fixed, constant symbols and labels for identification, signage and visualization. The OLEDs used for this purpose could simply be called “fixed OLEDs”, whereby the term “fixed” refers to the stationary, unchanging shape of the illuminating area of the illuminated display and not to any elastic properties of the light-emitting component itself.
In order to enable OLEDs to display symbols or letters in a stationary manner—i.e., to enable structured radiation—requires some modification of the device architecture over a standard device. The illuminating area of the OLED is generally determined by the zone, in which the anode and cathode overlap. By arranging the electrodes accordingly, it becomes possible to create fixed shapes, symbols and text. According to the state of the art, an ITO anode is applied and photolithographically etched and a shadow mask is used during thermal vapor-deposition of the cathode to deposit the cathode in a desired configuration. In view of the simple and economic processing of OLEDs for simple display elements, the photolithographic techniques are not well suited since this procedure requires a large number of processing steps, which make it a complex and time-consuming procedure. In addition, photolithography requires the use of chemicals, which are expensive to purchase and which may damage underlying layers.